Dental plaque is a mixed matrix of bacteria, epithelial cells, leukocytes, macro-phages and other oral exudate. Bacteria comprise approximately three-quarters of the plaque matrix. Any given sample of dental plaque could contain more than 400 different varieties of microorganisms. This mix includes both aerobic and anaerobic bacteria, fungi and protozoa. Viruses have also been found in samples of dental plaque.
This matrix of organisms and oral exudate continues expanding and coalesces with other plaque growths situated nearby. The bacteria synthesize levans and glucans from sucrose found in the oral cavity providing energy for the microorganisms. These glucans, levans and microorganisms form an adhesive skeleton for the continued proliferation of plaque.
The bacteria found in plaque can secrete acids, enzymes and toxins, which can cause caries, oral malodor and periodontal disease.
Periodontal disease (“gum disease”) is a broad term used to describe those diseases which attack the gingiva and the underlying alveolar bone supporting the teeth. The disease exists in a number of species of warm blooded animals including humans and canines, and includes a series of diseases exhibiting various syndromes which vary from each other according to the stage or situation of the disease or the age of the patient. The term is used for any inflammatory disease, which initially occurs at a marginal gingiva area and may affect the alveolar bone. Periodontal disease affects the periodontium, which is the investing and supporting tissue surrounding a tooth (i.e., the periodontal ligament, the gingiva, and the alveolar bone). Two common periodontal diseases are gingivitis (inflammation of the gingiva) and periodontitis (inflammation of the periodontal ligament manifested by progressive resorption of alveolar bone, increasing mobility of the teeth, and loss of the teeth at advanced stage). Combinations of inflammatory and degenerative conditions are termed periodontitis complex. Other terms used for various aspects of periodontal disease are “juvenile periodontitis”, “acute necrotizing ulcerative gingivitis”, and “alveolar pyorrhea”.
Periodontal disease may involve one or more of the following conditions: inflammation of the gingiva, formation of periodontal pockets, bleeding and/or pus discharge from the periodontal pockets, resorption of alveolar bone, loose teeth and loss of teeth. Periodontal disease is generally considered to be caused by/associated with bacteria, which are generally present in dental plaque which forms on the surface of the teeth and in the periodontal pocket. Thus, known methods for treating periodontal disease often include the use of antimicrobials and/or anti-inflammatory drugs.
Periodontal disease is a major cause of tooth loss in adult humans. Tooth loss from periodontal disease is a significant problem beginning at age 35, but even by age 15 it is estimated that about 4 out of 5 persons already have gingivitis and 4 out of 10 have periodontitis. While good oral hygiene, as achieved by brushing the teeth with a cleansing dentifrice, may help reduce the incidence of periodontal disease, it does not necessarily prevent or eliminate its occurrence. This is because microorganisms contribute to both the initiation and progress of periodontal disease. Thus, in order to prevent or treat periodontal disease, these microorganisms must be suppressed by some means other than simple mechanical scrubbing. Towards this end, there has been a great deal of research aimed at developing therapeutic dentifrices, mouthwashes, and methods of treating periodontal disease, which are effective in suppressing these microorganisms.
Malodor of the oral cavity is also known as halitosis or bad breath. It is broadly estimated that in the United States 20-90 million individuals have oral malodor. It is generally believed that the cause of this condition is due to the presence of anaerobic bacteria, especially gram-negative anaerobic bacteria, in the mouth. These bacteria will generate volatile sulfur compounds (VSC's) which are known to cause oral or breath malodor. It is also recognized in the art that oral malodor not only comes from the posterior dorsal surface of the tongue but also from periodontal pockets. Furthermore, a person with gingivitis or periodontal disease may have increased oral malodor from disintegrated epithelial cells. Epithelial cells turn over faster if inflammation is present. Therefore, a larger number of these dead epithelial cells remain in the oral cavity and will degrade into the malodorous compounds.
The use of mouthrinses comprising quaternary ammonium antimicrobials such as CPC to reduce or eliminate oral bacterial flora and oral malodor has been recognized for some time. Examples of previous disclosures include: U.S. Pat. No. 6,440,395 to Libin; U.S. Pat. No. 6,355,229 to Adamy; U.S. Pat. No. 6,344,184 to Rolla; U.S. Pat. No. 6,117,417 to Wicks et al.; U.S. Pat. No. 5,980,925 to Jampani et al.; U.S. Pat. No. 5,948,390 to Nelson et al.; U.S. Pat. No. 5,686,063 and U.S. Pat. No. 5,681,549 both to McLaughlin et al.; U.S. Pat. No. 5,560,906 to Scodari et al.; U.S. Pat. No. 5,407,664 and U.S. Pat. No. 5,292,527 both to Konopa; U.S. Pat. No. 5,405,604 to Hall; U.S. Pat. No. 5,374,418 and U.S. Pat. No. 5,370,865 both to Yamagishi et al., U.S. Pat. No. 5,286,479 to Garlich et al.; U.S. Pat. Nos. 5,525,330; 5,256,396; 5,158,763; 4,370,314; 4,339,430; 4,273,759; 4,224,309; 4,188,372; 4,137,303; 4,123,512; 4,118,476; 4,118,475; 4,118,474; 4,118,473; 4,118,472; 4,110,429; 4,102,993; 4,100,270; 4,089,880; 4,080,441; 4,042,679; and 3,864,472 and WO 03/075865 (all assigned to Colgate Palmolive); U.S. Pat. No. 4,994,262 to Charbonneau et al.; U.S. Pat. Nos. 4,959,204; 4,663,154 and 4,472,373 all to Ryan; U.S. Pat. No. 4 4,325,939 to Shah; U.S. Pat. No. 4,323,551, to Parran, Jr.; WO 96/15770, WO 94/27566 and WO 94/18939 (all assigned to Warner-Lambert); WO 00/44338 (assigned to Bioglobe Tech., Inc.).
While quaternary ammonium antimicrobials such as CPC have long been used in oral mouthrinses, there is still a need for additional formulations, which provide enhanced antimicrobial activity along with increased user acceptance. The present invention relates to mouthrinse compositions that provide increased bioavailable levels of a quaternary ammonium antimicrobial and thus, improved efficacy. The compositions are formulated to be essentially free of anionic, nonionic or amphoteric surfactants. Surfactants are normally employed to achieve dispersion of water insoluble additives such as flavoring oils in oral care compositions. The present inventors have discovered that the presence of such surfactants in compositions containing quaternary ammonium antimicrobials can significantly inhibit their activity. Specifically the use of surfactants has been found to decrease the amount of bioavailable antimicrobial and is therefore deleterious to achieving acceptable bactericidal efficacy. The present mouthrinse compositions are thus formulated to be essentially free of such anionic, nonionic or amphoteric surfactants, resulting in enhanced bactericidal efficacy of the compositions, while surprisingly being aesthetically pleasing.